Method and apparatus for hardware forwarding of LAN frames over ATM networks

A local area network (LAN) switching apparatus for interconnecting a LAN segment to an Asynchronous Transfer Mode (ATM) network, comprising:

• a plurality of LAN ports, wherein each LAN port connects one unique LAN segment to a LAN switch;
• at least one ATM port, wherein each ATM port of the LAN switch interfaces to the ATM network;
• a connection means for establishing a plurality of connection paths simultaneously, wherein each said connection path establishes a connection through the switching apparatus between any two or more of the plurality of LAN ports and ATM ports, said connection path for transmitting data comprising LAN frames;
• a data transmission means for formatting data for transmission over said LAN into standard LAN frames in compliance with the international standard of Open Systems Interconnection (OSI), wherein said standard provides a universally applicable layered architecture containing seven layers, numbered from 1 to 7, with each layer having a set of defined functions and providing a set of services to and from the adjacent two layers;
• and
• a LAN to ATM format conversion means for changing the format of data as it traverses the LAN switch from LAN port to switch to ATM port, wherein LAN frames are converted to switch frames for transfer through the switching apparatus and switch frames are converted to ATM frames in preparation for transfer to the ATM network;
• an ATM adapting apparatus for converting ATM frames to ATM network format and ATM network format to ATM frames, wherein ATM network format comprises segmenting said ATM frame into sequential ATM cells comprising 5 bytes of header and 48 bytes of data;
• and
• a first multiprotocol processing means, wherein said LAN switch converts either layer 2 or layer 3 of the OSI standard from LAN frames to switch frames to ATM frames, wherein LAN frames are compatible with LAN protocol and ATM frames are compatible with the first ATM adapting apparatus protocol.